Air based cargo delivery systems (e.g., parachute based delivery) are frequently used to drop cargo or persons from an aircraft and control descent (e.g., speed) of the cargo such that the cargo may land safely and be recovered by a ground team. To accomplish this task, an item of cargo may be equipped with a parachute system, including a parachute container, a parachute, a restraint release device (e.g., a cut-knife), and a static line connected to the parachute container and canopy, among other things. This parachute system may initially be affixed to the cargo item via one or more lengths of restraint material (e.g., nylon cord) in preparation for transport to a desired location via an aircraft.
Prior to the cargo exiting the aircraft at altitude, one end of the static line may be connected to an anchor in the aircraft such that, upon exit of the cargo, tension may be applied to the static line causing the restraint release device to release (e.g., cut) the segments of material affixing the parachute system to the cargo. Once these segments are cut, the static line may cause the parachute container to be opened and the canopy to separate from the static line and parachute container. The dangling static line and parachute container may then be retrieved and brought into the aircraft by aircraft personnel.
In some circumstances (e.g., high altitude delivery) it has been desirable to utilize a “release away” or “breakaway” static line to eliminate the need for a crewman to retrieve the static line and parachute container from outside the aircraft. These release away static lines may include a “U” connector between two segments of static line, and a locking loop configured to hold the U connector in place, among other things. When tension is applied to such a static line, the force required to release the U connector from the locking loop and achieve the “release away” may increase exponentially with the amount of tension present in the static line. Twisting of the releasable static line also may further increase forces associated with release. Testing of some releasable static lines has demonstrated that where 100 pounds of tension is applied to a straight releasable static line, 200 pounds of force, or more, may be used to release the U connector.
Also adding to the forces associated with the releasable static line may be a force associated with a restraint release device for releasing the parachute container from its pre-drop location. Prior art “cut-knives” used for such purposes may dull quickly (e.g., as a result of excessive force), resulting in additional force to cause the cutting of the restraint material. In some instances, it has been determined that in excess of 400 pounds of force has been used to cut the restraint material.
Large forces exerted on the releasable static line, such as from the release-away and restraint release systems, may cause problems such as recoil of the static line and subsequent damage to the aircraft, parachute system, and/or aircraft crew. Therefore, it may be desirable to limit the force necessary to cause the release away of a releasable static line associated with a parachute.
Further, previous restraint release devices have suffered from other issues such as, their inability to be reused based on sharpening difficulties. Therefore, using and replacing such devices can may become cost ineffective.
The present disclosure is directed to addressing one or more of the desires and issues discussed above utilizing various examples of a releasable parachute deployment line and/or restraint release device.
Although the present invention may obviate one or more of the above-mentioned needs, it should be understood that some aspects and embodiments of the invention might not necessarily obviate one or more of those needs.